Persia was long a fault-line in an Islam that liked to think of itself, and was often presented as being, monolithic. Notwithstanding the best efforts of the Umayyad Caliphate—which defeated the Persian Sassanids in the 7th century—at both Arabization and Islamization, linguistic, cultural and even religious divisions remained. Persian identity began to reassert itself soon thereafter and the turn the of 10th century, the rise of  the Ghaznavids constitute a very intriguing period from the point of view of flourishing of Persian literature, art, music, philosophy, and contribution in science and mathematics.